It's perfectly fine the way it is, that's game dev. I bet txesmi has found the reason for why it behaves like it does.
In case you need deterministic/ framerate independent outcome (which you normally do NOT need), use a lockstep or fixed step approach and blend the visuals between old and new pos. I do/ did that for some multiplayer stuff, that's it.
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual
